1. Field of the Invention
The invention relates to a bone joint prosthesis, and more particularly to an elbow joint prosthesis used to replace a dysfunctional elbow joint.
2. Description of the Related Art
A variety of devices have been developed for elbow prosthetic reconstruction. Some commercially available prosthetic elbow replacement systems include: the Coonrad/Morrey Total Elbow available from Zimmer Inc., the Solar® total elbow system available from Stryker Orthopaedics, the Texx total elbow system available from Biotek, and the Discovery™ total elbow system available from Biomet. Various U.S. patents and U.S. patent applications also describe elbow joint prostheses, bone joint prostheses, and related instrumentation and procedures. See, for example, U.S. Pat. Nos. 2,696,817, 3,772,709, 3,816,854, 3,868,730, 3,939,496, 3,990,117, 4,008,495, 4,079,469, 4,131,956, 4,280,231, 4,293,963, 4,383,337, 4,538,306, 5,061,271, 5,314,484, 5,376,121, 5,723,015, 5,782,923, 5,954,770, 6,027,534, 6,290,725, 6,379,387, 6,699,290, 6,716,248, 6,767,368, 6,890,357, 6,997,957 and U.S. Patent Application Publication Nos. 2003/0208276, 2003/0232124 and 2005/0043806.
While these known prosthetic elbow replacement systems may be acceptable for certain applications, under certain circumstances some prosthetic elbow replacement systems have disadvantages. For instance, wear debris is one concern with respect to implant replacement of the elbow. This typically occurs if the humeral and ulnar stems are well fixed. The spectrum of pathology requires that a replacement is sometimes indicated in elbows with gross deformity. Thus, a stable implant that can tolerate the stresses at the stem bone interface and still provide some play at the articulation to lessen the likelihood of loosening is ideal. Yet wear of the articulation can occur under these circumstances.
Thus, there exists a need for an improved prosthetic elbow replacement system that addresses: (i) the instability of unlinked implants, (ii) the need for better wear characteristics than are now available in current linked implants, (iii) the need for a unique design of the ulnar component that lessens the possibility of malalignment, and (iv) the need for a design that allows the implant to be put in without cement should this be desired.